Genetic and environmental variation in wood properties of Acacia melanoxylon

Acacia melanoxylon in Argentina: heartwood content and its relationship with site, growth and age of the trees

“…These authors, working on 45-year-old trees (DBH= 40 cm) determined values of 3.1-3.5 cm along the tree, which, as in the present work, could be considered as an axially constant thickness. In A. melanoxylon plantations in New Zealand, Haslett (1986) pointed as usual a thickness of 2-5 cm, whereas in 18-year-old trees (DBH= 15.3 cm) in Tasmania, Bradbury et al (2011) reported a thickness of 2.7 cm, values that are in agreement with that observed in this study. On the other hand, a constant thickness of sapwood along the stem has also been observed in other commercial genera such as Eucalyptus (Hillis, 1987;Taylor et al, 2002;Miranda et al, 2009).…”

“…In addition, all the trees presented heartwood along the stem, which is an important aspect for the potential use of this wood destined to sawing (Searle & Owen, 2005;Bradbury et al, 2011). In contrast to that reported for A. melanoxylon trees of higher commercial sizes (DBH 40 cm, TH 39 -42 m), where the height reached by the heartwood was on average 81% of the total height (Knapic et al, 2006), we did not observe a free height level of heartwood.…”

“…Several authors consider the age of the trees as the main factor that control the contents of heartwood and sapwood (Harrison, 1974;Stokes & Berthier, 2000;Taylor et al, 2002;Climent et al, 2002Climent et al, , 2003Bradbury, 2005;Searle & Owen, 2005). It has also been found that the content of heartwood is related to the growth rate, the site, the silvicultural practices, and a moderate genetic control (Hillis, 1987;Zobel & Jett, 1995;Taylor et al, 2002;Knapic et al, 2006;Gominho & Pereira, 2000, 2005Miranda et al, 2009;Bradbury et al, 2011). However, in the present study, we found no significant linear relationship between the heartwood content (both in relative and absolute terms) and the age, at least at the age ranges that characterized this material (9-32 years).…”

“…In the plantations in Portugal studied by Knapic et al (2006) and Santos et al (2013), these authors did not detect variation among sites, differentiated primarily by their thermal and water regimes. The size/ heartwood or growth/heartwood ratios (conditioned by the site/genotype and the interaction between them) have been referred to as having a positive nature in A. melanoxylon, at both the phenotypic and the genetic levels (Harrison, 1974;Knapic et al, 2006;Bradbury et al, 2011), as well as in other species (Knapic & Pereira, 2005;Gominho & Pereira, 2000, 2005. This is consistent with that found in this work: high correlation between DBH, TH and stem volume and heartwood content (Table 5), as well as higher heartwood content in the trees from LT and MCh, sites that represented the best places from the biometric point of view (Table S1 [supplementary], for more information see Igartúa, 2013).…”

“…For more than one century, the wood of this tree has been internationally considered as one of the most decorative in the world, belonging to the same category as that of the walnut, mahogany and teak (Nicholas & Brown, 2002;Bradbury et al, 2011), and has been the mainstay of the fine furniture industry in Tasmania (Tasmanian Timber Promotion Board, 2012).…”